Matching images by comparing their gradient fields

We present a simple yet powerful method to perform point-to-point matching between two images. The method uses an evidence measure, whose value for a given displacement reflects both the similarity between two locations and the confidence in a correct match. The measure is based on the gradient fields of the images, and can be computed quickly and in parallel. Accumulating the evidence measure for different displacements allows (1) stable computation, of correspondences without smoothing across motion boundaries, and (2) detection of dominant motions. The method works well both on highly textured images and on images containing regions of uniform intensities, and can be used for a variety of applications, including stereo, motion, and object tracking.